Morphological synthesis of Prussian blue analogue Zn3[Fe(CN)6]2⋅xH2O micro-/nanocrystals and their excellent adsorption performance toward methylene blue

Abstract

Prussian blue analogue Zn3[Fe(CN)6]2⋅xH2O (Zn-PBA) micro-/nanocrystals with well-defined spherical, cubic and polyhedral morphologies have been successfully synthesized by a simple room-temperature solution method. The morphologies and sizes of the micro-/nanocrystals can be easily tuned by HCl dosage and polymer additive. The as-prepared products are characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and Brunauer Emmet Teller adsorption–desorption analysis. The possible formation mechanism for these Zn-PBA micro-/nanocrystals is then proposed. In addtion, adsorption performances of these micro-/nanocrystals toward organic dyes are systematically investigated. It is demonstrated that they exhibit strong adsorption selectivity to methylene blue (MB) with an extraordinary adsorption capacity as high as 1.016gg−1 due to the proper pore size and large specific surface area (643.2m2g−1) of the product as well as the strong electrostatic interaction between MB molecules and Zn-PBA particles. It is found that the morphology and size of the micro-/nanocrystals have an important effect on their adsorption performance. Moreover, the adsorbed MB dye can be well released in some organic solvents such as ethanol and trichloromethane. The facile morphology-controlled synthesis and excellent adsorption property afford the materials promising application in adsorption related fields.